1. Field of the Invention
This invention relates to track-and-trolley conveyor guide apparatus, specifically to such systems that fill material into or recover material from a plurality of storage bins.
2. Discussion of Prior Art
A significant cost in designing feed mills, grain elevators, seed conditioning plants, industrial bulk material handling, storage, and processing facilities, and the like is the conveying system. These facilities generally use a conveying system to distribute or reclaim material. A distribution conveying system normally retrieves material from process equipment or another conveyor and moves it to a bin, another conveyor, or process equipment. A reclaim conveyor system generally collects material from the discharge opening of a storage bin and moves it away from the storage bin. Facilities with distribution or reclaim conveying systems typically require many linear meters of conveying equipment to serve the material handling requirements. Such equipment can be costly, not only in actual price, but also in terms of maintenance and energy requirements.
With the onset of increased purity requirements worldwide, one must also consider cross-contamination issues when choosing methods of conveyance for distribution or reclaim. Cross-contamination is the inadvertent intermingling of one product with another. In storage facilities that handle many different types of products, preventing or minimizing cross-contamination can be of particular concern, not only for product quality reasons, but also to minimize liability purposes. Efficiency and good cleanout, where little or no product remains on the conveyor after it reaches its destination, are two characteristics of conveying systems that are highly desirable in the these types of industries.
Current methods of conveying products to or from storage bins generally require a relatively large amount of linear meters of conveyors. Often, the design of the distribution system requires multiple points of discharge prior to the end discharge of the conveyor. These intermediate discharge gates can often be sources of cross-contamination since they are hard to cleanout. Filling into or recovering material from an array of bins using conventional methods often requires many linear-meters of conveying equipment, multiple intermediate discharge gates for distribution (which are sources of cross-contamination), and a relatively large amount of energy to run the equipment.
Preventing cross-contamination has become a priority in the animal feed, grain, and seed industries. Cross-contamination issues have become prevalent in recent years due to several factors, such as increased demand for identity preserved traits, the development of transgenic organisms, and food security in general. Transgenic organisms specifically refer to organisms that have genes that were transferred from an unrelated organism. The term genetically modified organisms (GMO) is a broader term that includes transgenic organisms. For the purpose of this disclosure, a distinction between these two terms will not be made. Processors increasingly demand quality products with characteristics that are best suited for a desired end product. Governments have more strict purity requirements regarding the amount of GMO allowed in conventional (non-transgenic) products. Consumers also desire segregation of transgenic from non-transgenic products. Other security concerns include trace-to-origin and other traceability requirements and issues, as well as ensuring that varieties or hybrids with different end-use purposes are not commingled. Thus, the more conveyors that are used to distribute or reclaim materials, the more opportunity for cross-contamination. Efficiency and good cleanout, where little or no product remains on the conveyor after it reaches its destination, are two characteristics of conveying systems that are highly desirable in the these types of industries.
Mounting international pressure to trace ingredients to points of origin has also contributed to the need to further prevent cross-contamination, and to segregate ingredients. Segregated storage is a concept that is gaining acceptance in the grain and feed industries since it can enhance value of stored products and help minimize the potential risks associated with foodborne diseases and bioterrorism. Products can be differentiated by such characteristics as the following: (a) ingredient origin, (b) plant variety, (c) protein level, (d) moisture level, (e) quality, (f) particle size, (g) field origin, (i) growing conditions, (k) foreign matter level, and (l) transgenetic status. Segregated storage and tracing ingredients to their points of origin have recently become even more important in these industries, not only because of regulations put forward by the European Union, but also due to the first documented case of Bovine Spongiform Encephalopathy, or Mad Cow Disease, in the United States. A diseased dairy cow is believed to have contracted the illness from contaminated feed. Efficient segregated storage, aided with a conveying system that greatly reduces or virtually eliminates the chance of cross-contamination, is a fundamental tool in complying with trace-to-origin regulations, and in reducing risks associated with cross-contamination in general.
Attempts have been made to reduce the number of linear meters of conveyor required to distribute to or reclaim from a plurality of bins. Examples of such conveying systems include those disclosed in the following patents: U.S. Pat. No. 4,330,232 to McClaren et al., 1982; U.S. Pat. No. 3,197,044 to Hozak et al., 1965; U.S. Pat. No. 4,491,216 to Sawby et al., 1985 US 2003/0113194 to Stafford & Elder et al., 2003; U.S. Pat. No. 3,435,967 to Sackett et al., 1969; U.S. Pat. No. 2,721,665 to Goeke et al., 1955; U.S. Pat. No. 4,619,576 to Kurudamannil et al., DE Patent 270,042 to Muth-Schmidt et al., 1912; and GB Patent 752, 816 A to Hessling et al., 1956.
McClaren attempts to fill a plurality of bins arranged in circular arcs about a central pad with one-wheel trolleys. Limitations of this arrangement include the following: (1) the use of steep incline screw conveyors creates cross-contamination issues, since they are not easily completely cleaned of product; (2) rotation is limited by product receiving area requirements; (3) multiple conveyors are needed to reach outlying bins; (4) the design requires a relatively large footprint, which may be limiting in many facilities; and (5) the rotational axis is controlled by a center support.
Hozak shows a device somewhat similar to McClaren's, except it uses belt conveyors. In Hozak's design, the system once again requires a relatively large footprint, and as the height of the bins increase, so does the floor space requirement. This system also requires significant space above the bins. Consequently, very tall roofs, known as head houses, are required if this system were used in enclosed multi-silo structures. The rotational axis of Hozark's conveying system is also controlled and maintained by a central support device.
Sawby shows a swiveling conveying system for filling or reclaiming material from a plurality of storage bins. This system has an extendable auger at the end of a boom that pivots around a mast, and is limited to filling only one arc of receptacles. This system also requires a large footprint, and cleanout is relatively difficult. Although this system has the ability to both distribute to and reclaim from a plurality of bins, a fixed mast and boom locates the permanent axial position of the conveyor. Sawby's apparatus would not be practical for multiple rows of bins, or for conveyors with high volumes that would create heavy loads onto the boom and mast.
The conveying system disclosed by Sackett is functionally limited to square or rectangular bins, and it requires multiple conveyors. Although this system does not rely on a central support device, the one wheel trolley's rest on a track. There are not any provisions in this apparatus for the conveyor to withstand uneven downward, upward, or lateral forces. There are no provisions for use on an arcuate trace.
Stafford and Elder's device requires a large footprint and is limited to one type of structure. This apparatus also pivots about a central axis. The wheels rest upon a track and do not provide significant guidance.
The Goeke system has one wheel trolleys resting upon a track and does not have a mechanism at a central axis but its conveyor does not have any means of staying on the track if it is subjected to upward, uneven downward, lateral, or radial forces. Goeke's apparatus would have difficulty with a cantilevered conveyor or an inclined conveyor. If a foreign object were on the track of this system, the wheels would have a tendency to jump over the object and depart from the track, rather than being blocked and coming to a stop.
The Kurudamannil system is very similar to Sackett's, with one-wheel trolleys resting on a track, but with a conveyor pivoting on a shaft to transfer to other conveyors. The trolley system is not designed to provide any contribution beyond providing a linear guidance and weight support.
Muth-Schmidt uses a circular track that is fully supported and controlled by a central support and control mechanism. The one-wheel trolley system does not provide for significant guidance but is instead primarily used for supporting the weight. A circular track that is supported and controlled from a central mechanism has several limitations such as the following:    a. incline conveyor stresses a central mechanism,    b. the cantilevered conveyors stresses the central support, and    c. difficult to control long conveyors from a central mechanism.
Hessling's apparatus is a traversing conveyor that is controlled by a central support mechanism that maintains a fixed central axis supporting a circular track. The upper conveyor has a fixed location. The one-wheel trolley on a circular track is not used for guidance, but is instead primarily used for weight support of the upper conveyor. The lower conveyor rotational capability is less than 180° due to the supports of the upper conveyor resting on the track. Hessling's apparatus would not be suitable for multiple concentric tracks, tall silos, long-heavy-high-volume conveying systems, or systems that require more than 180° of rotational capability.
The majority of the prior art cited rotates around a central axis for support, control, and placement of conveyor. The remaining relevant prior art relies on a simple trolley system that does not provide significant guidance to the conveyor when subjected to uneven, lateral, or radial forces. As far as I am aware, there is not a track-and-trolley conveyor guidance system designed to withstand uneven, lateral, or radial loads without a central support mechanism while maintaining guidance to the conveyor. All of the prior art cited uses a one-wheel trolley.
Other conventional methods of distributing material to or reclaiming material from multiple silos include belt, drag chain, or screw conveyors. These traditional conveyor systems have at least one stationary conveyor positioned above or below the length of the silos to distribute material into or recover material from the silos. This requires many linear meters of conveyance. These traditional distribution conveyor systems incorporate multiple intermediate discharge gates so the conveyor can discharge at multiple points along the conveyor. The problem with conventional distribution conveyors is that the intermediate discharge gates tend to have carryover problems that can cause potential cross-contamination. If the entire product does not fall through the open intermediate discharge gate, the product can be conveyed to an unintended storage bin. Also, intermediate discharge gates on a conventional conveyor tend to seal imperfectly with the conveyor trough, creating further cross contamination potential.
An alternative to using conveying systems to fill bins, like those described above, is down-spouting. Down-spouting is typically pipe at a 38 degree or steeper angle that flows the grain or ingredients to a silo. However, down-spouting requires a relatively tall head house if it is to be enclosed, often about 10 m to 20 m above the bins to be filled. Material moving along long lengths of down-spouting can reach relatively high speeds, and thus can land harshly within a bin. Such impacts can significantly lower product quality, and so, in many cases, down-spouting is undesirable. There are also cross-contamination issues with the conventional methods of directing grain or ingredient flow to one of multiple downspouts.
In summary, the following are typical disadvantages of conventional conveying or spouting systems that are used to fill a plurality of bins:    (a) multiple long conveyors are usually needed, requiring many linear meters of conveyor, which increase cross-contamination risk and adds to energy and maintenance costs;    (b) multiple discharge gates on the conveyor are often necessary for distribution, which increases risk of cross-contamination; and    (c) some of the prior-art apparatuses have inherent cross-contamination or commingling problems.
In summary, the following are typical disadvantages of conventional trolley assisted conveying systems to fill a bin residing within a cluster of bins:    (a) a central shaft or central support mechanism is usually required to maintain the center of axis;    (b) existing trolley designs do not show mechanisms to withstand upward, downward, lateral, uneven, and/or radial forces, while maintaining desired guidance;    (c) prior art systems do not confine movement to only the desired linear or radial path;    (d) a central support device that can withstand substantial loads when supporting and/or controlling long and/or heavy conveyance systems might not be feasible with most storage silos;    (e) a single wheel trolley assembly that only rests on a track cannot withstand upward, uneven downward, lateral, and/or radial forces;    (f) many of the prior art systems increase the roof height requirements above the silos;    (g) some of the cited prior art would only be practical with one type of conveyance such as a screw type conveyor and would not be suited for other types of mechanical conveyors; and    (h) some of the prior art apparatuses have inherent cross-contamination or commingling flaws.
One reason a track-and-trolley guided reclaim conveyor system has not been incorporated to collect and convey material from storage receptacles in the past is because of the requirement to move the conveyor between the bin support legs. As a result, the traditional bin reclaim system has had a stationary conveyor(s) positioned under the length of the silos to reclaim the material from the silos and then discharge the material away from or near the perimeter of the silos. This requires many linear meters of conveyance.
In summary, the following are typical disadvantages of conventional conveying systems to recover material from a plurality of bins:    (a) many linear meters of conveyor are needed, which increases cross-contamination risk and adds to energy and maintenance costs;    (b) some of the prior art apparatuses have inherent cross-contamination or commingling flaws;    (d) conventional conveying systems may require a central shaft or mechanism to maintain an axis, support the conveyor, or to control the conveyor; and    (e) conventional conveying systems have no mechanism to move a conveying device under storage bins and between storage bin support legs.